The A-223 pulleys are supposed to fit cable sizes from 1/16 to 1/8 inch, and the rudder cable supplied in the Onex kit (at least the one in mine) is 1/8 inch and fits nicely in the pulley groove. The problem with the cable coming out of the grove might be caused by misalignment of the pulley. Sonex, as I recall, specifies that the plane of the pulley should align with the plane formed by the entering and exiting cable segments to within 7 degrees. Zero degrees is better, as it will pretty much eliminate wear on the pulley groove. I'd recommend checking all your pulley alignments. Also, as a safety precaution, all pulleys should be fitted with cable guards. These can be purchased but are quite simple to fabricate. Here is a photo of a guard mounted to one side of the pulley block. There is about 1/32-inch clearance between the guard and the rim of the pulley.
- Pulley with cable guard
Regarding the rudder pedal rigging: The procedure that Sonex prescribes for this works pretty well with one big exceptions. If you elect to move the rudder pedals aft (to accommodate a shorter pilot), this with change the angle at which the cable and cable adjuster meet the pedal. The result is that you will run out of rudder travel at the point when the cable begins to pull radially on the pedal, that is, in the full pedal-aft position. This will occur before the rudder hits the stops. The only solution to this appears to be to move those first two pulleys aft by the same amount as you moved the rudder pedals. This will keep the angle the same, and the rigging procedure will still work.
Regarding the springs, the ones in my kit proved to be way too large. I ended up using Hillman #25 extension springs (OD 13/32 in, length 2 3/4, wire size 0.041 in, zinc plated). They seem to work well.